feat(app): 完善播放协议搜索与空状态

lib/pages/auth/auth_legal_links.dart

@@ -0,0 +1,75 @@
+// Author: fruit.com.cn
+
+import 'dart:async';
+
+import 'package:flutter/gestures.dart';
+import 'package:flutter/material.dart';
+
+import '../../core/legal/legal_opener.dart';
+import '../../core/legal/legal_page.dart';
+import '../../core/theme/app_colors.dart';
+import '../../l10n/app_localizations.dart';
+
+const double _legalFontSize = 12;
+
+/// 登录页底部的协议入口。点用户协议或隐私政策会打开对应语言的页面。
+class AuthLegalLinks extends StatefulWidget {
+  const AuthLegalLinks({super.key, this.open});
+
+  /// 测试时可替换真正的跳转。
+  final Future<void> Function(String url)? open;
+
+  @override
+  State<AuthLegalLinks> createState() => _AuthLegalLinksState();
+}
+
+class _AuthLegalLinksState extends State<AuthLegalLinks> {
+  late final TapGestureRecognizer _termsTap = TapGestureRecognizer()
+    ..onTap = () => _open(legalTermsPath);
+  late final TapGestureRecognizer _privacyTap = TapGestureRecognizer()
+    ..onTap = () => _open(legalPrivacyPath);
+
+  @override
+  void dispose() {
+    _termsTap.dispose();
+    _privacyTap.dispose();
+    super.dispose();
+  }
+
+  void _open(String path) {
+    final url = legalPageUrl(path, Localizations.localeOf(context));
+    final custom = widget.open;
+    if (custom != null) {
+      unawaited(custom(url));
+      return;
+    }
+    unawaited(openLegalUrlOrNotify(context, url));
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final l10n = AppLocalizations.of(context)!;
+    final muted = TextStyle(color: AppColors.muted, fontSize: _legalFontSize, height: 1.6);
+    final link = muted.copyWith(color: AppColors.blue);
+    return Text.rich(
+      TextSpan(
+        style: muted,
+        children: [
+          TextSpan(text: l10n.authLegalLead),
+          const TextSpan(text: ' '),
+          TextSpan(text: l10n.authTerms, style: link, recognizer: _termsTap),
+          const TextSpan(text: ' '),
+          TextSpan(text: l10n.authLegalJoin),
+          const TextSpan(text: ' '),
+          TextSpan(
+            text: l10n.authPrivacy,
+            style: link,
+            recognizer: _privacyTap,
+          ),
+        ],
+      ),
+      key: const Key('auth-legal'),
+      textAlign: TextAlign.center,
+    );
+  }
+}